Injection head, mixing space and power unit

ABSTRACT

An injection head for injecting fluids into a mixing space is provided, comprising a porous plate with a concave first side, which faces the mixing space, and with a second side, a partition with a first side, which faces the second side of the porous plate, and with a convex second side, at least one fluid supply space, which is arranged between the partition and the porous plate, and a plurality of injector elements, which run through the partition and the porous plate and in each case open with an outlet into the mixing space.

This application is a continuation of international application number PCT/EP2007/005287 filed on Jun. 15, 2007.

The present disclosure relates to the subject matter disclosed in international application number PCT/EP2007/005287 of Jun. 15, 2007 and German application number 10 2006 029 586.2 of Jun. 20, 2006, which are incorporated herein by reference in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to an injection head for injecting fluids into a mixing space.

The invention also relates to a mixing space.

The invention furthermore relates to a power unit, comprising a combustion chamber and a nozzle, which is arranged on the combustion chamber, with a nozzle wall.

A combustion chamber is known from WO 99/04156, in particular for a rocket power unit, which comprises a combustion space, an inner casing surrounding the combustion space and an outer casing surrounding the inner casing. Coolant channels are configured between the inner casing and the outer casing.

An injection head for supplying medium bringing about a combustion in a combustion space is known from DE 10 2004 029 029 A1 and is constructed from at least two segments interlocking coaxially to an axis. The at least two segments have at least one distribution channel with an associated elongated outlet region for a flow of a first medium and at least one distribution channel with an associated elongated outlet region for wall regions delimiting a flow of a second medium. The elongated outlet region for the first medium and the elongated outlet region for the second medium are coaxial to one another and configured peripherally at least in an angle range of 360° about the axis.

SUMMARY OF THE INVENTION

In accordance with the present invention, an injection head for injecting fluids into a mixing space is provided, by means of which a mixture with a high degree of homogeneity can be achieved over a short section.

In accordance with an embodiment of the invention, the injection head comprises a porous plate with a concave first side, which faces the mixing space, and with a second side, comprises a partition wall with a first side, which faces the second side of the porous plate, and with a convex second side, comprises at least one fluid supply space, which is arranged between the partition wall and the porous plate, and comprises a plurality of injector elements, which run through the partition wall and the porous plate and in each case open with an outlet into the mixing space.

A high contact surface for injected fluids into the mixing space can be achieved with a high compressive strength by a cupola-shaped configuration of the partition wall and the porous plate.

One or more fluids can be injected by way of the injector elements and one or more fluids can be injected by way of the porous plate into the mixing space. As a result, a rapid and homogeneous distribution of the fluids in obtained. In particular, a reaction zone can be minimized.

A rapid decay of the jet is obtained by means of the injector elements. As a result, the length of the reaction zone can be kept small. As a result, in turn, the mixing space can be produced in a space-saving and weight-saving manner.

The injection head can be produced in a simple manner. For example, the porous plate is produced with bores, into which the injector elements are inserted. The injector elements are, for example, metallic or ceramic tubes, which can be produced in a simple manner. The injector elements can easily be fixed to the partition wall, for example by means of welding. Automatic fixing, for example by means of a welding robot is possible, in particular.

The injection head can be adapted to the special application by the arrangement and configuration of the individual injector elements. An adaptation in the direction of optimal atomization and mixing of the fluids, which are, in particular, reactants, can be achieved.

The fluid is supplied into the mixing space by way of the entire surface of the injection head toward the mixing space. This ensures a maximum utilization of space. Furthermore, there is achieved a high degree of tolerance with respect to local deviations, which may be due to the production or may occur during operation.

It is favorable if the porous plate has an open-porous structure. As a result, a fluid can be injected by way of the at least one fluid supply space between the partition wall and the porous plate through the porous plate into the mixing space.

It is basically possible for the porous plate to be produced, for example, from a metallic material such as, for example, a sintered material. It is advantageous if it is produced from a ceramic material to provide an injection head with a low weight. This is in turn very advantageous for use in a missile and, in particular, in a rocket, in order to be able to increase the useful load. Possible ceramic materials are C/C ceramic materials or oxide ceramic materials.

It is quite particularly advantageous if the partition wall is fluid-tight. This allows a separation to be achieved between the fluid(s) which are injected by way of the injector elements into the mixing space, and the fluid(s) which are injected by way of the porous plate.

It is favorable if the first side of the partition wall is concave. This allows the partition wall to be produced in a simple manner. It is then, in particular, dome-shaped or cupola-shaped and withstands high pressure loads.

It is favorable if the first side of the partition wall is substantially parallel to the first side of the porous plate. This allows the injection head to be produced in a simple manner and the fluid supply space can be provided in a simple manner.

For the same reason it is favorable if the first side and the second side of the partition wall are substantially parallel to one another.

It is also favorable if the second side of the porous plate is convex. As a result, the compressive strength of the porous plate is optimized with respect to fluid pressure in the fluid supply space.

It is furthermore favorable if the second side of the porous plate and the second side of the partition wall are substantially parallel to one another. This allows the injection head to be produced in a simple manner.

For the same reason it is favorable if the first side and the second side of the porous plate are substantially parallel to one another.

It is quite particularly advantageous if the injector elements in each case have an inlet which opens into at least one further fluid supply space. Fluid can thus be introduced by way of this inlet into the injector elements and can then be injected into the mixing space. The further fluid supply space is in this case used in particular as a distribution space for introducing fluid into the different injector elements.

It is favorable if the further fluid supply space is delimited by the partition and a cover element. The cover element is in particular an outer cover element of the injection head. For example, this injection head can be fixed to a mixing chamber or combustion chamber by means of the cover element. The cover element may be produced, for example, from a ceramic material.

The injector elements are, in particular, configured so as to be fluid-tight between an inlet and the outlet, in other words fluid, which is introduced into the inlet, can only leave the injector element through the outlet. This means that fluid from the further fluid supply space can be injected by way of the injector elements into the mixing space while flowing through the partition wall, the fluid supply space between the partition and the porous plate, and the porous plate, with the fluid not coming into contact with the further fluid injected by way of the porous plate.

It is favorable if the injector elements pass through the fluid supply space between the porous plate and the partition wall. As a result, a high surface density area of injector elements can be arranged in relation to the first side of the porous plate in order to achieve a high degree of mixing (with a high degree of homogeneity) with a short mixing section.

It is favorable in terms of production if the injector elements are tubular. These can then be produced in a simple manner. Furthermore, they can be positioned in a simple manner on the injection head during the production thereof.

In particular, the injector elements are straight, so that they can be produced in a simple and economical manner. Furthermore, they can be easily positioned during production.

It is favorable if the injector elements have a cylindrical annular casing. In particular, an injector element is then configured as a cylindrical tube, which can be correspondingly economically produced. In particular, the annular casing is produced from a metallic or ceramic material.

Advantageously, the injector elements are fixed to the partition wall and/or the porous plate. As a result, the injection head can be produced in a simple manner. For example, the injector elements are fixed to the partition wall by welding or soldering. As a result, the injection head can also be produced in a simple manner; for example, the porous plate is produced with recesses for injector elements. The injector elements are then introduced into the porous plate and the partition wall attached. The injector elements are then fixed to the partition wall, for example by welding or soldering. It is, for example, also possible for the injector elements to be fixed to the partition wall and for this combination of injector elements and partition to be attached to the porous plate.

It may be provided that the injector elements are arranged uniformly distributed. In particular, the spacing of outlets (mouth openings) into the mixing space of adjacent injector elements is substantially the same. A non-uniform arrangement may also be provided depending on the application.

In one embodiment, at least one injector element is configured as an igniter. This allows the ignition of a combustible fluid mixture in the mixing space to be facilitated or brought about.

In particular, the injector element(s), which are configured as igniters, are arranged centrally and, in particular, on or in the region around an axis of the injector head. This allows optimized ignition conditions.

It is favorable if the injection head has an axis, on which the centre point of a sphere of curvature of the first side of the porous plate and/or the second side of the partition wall is located. A high level of symmetry conditions, by means of which the mixture in the mixing space is improved, are achieved as a result.

It may be provided that injector elements are arranged distributed about the axis, in other words have different (planar) angular spacings from this axis.

It is furthermore favorable if injector elements are arranged distributed with respect to the angle of their respective longitudinal axis to the axis of the injection head, in other words if there is a distribution in the azimuthal angle.

In one embodiment, the longitudinal axes of the injector elements intersect a plane containing the axis of the injection head. It may be provided in this case that the longitudinal axes of the injector elements intersect the axis of the injection head or the longitudinal axes of the injector elements even intersect at one point. The arrangement and orientation of the injector elements depends on the special application.

In one embodiment, all or the majority of injector elements are arranged inclined with respect to the axis of the injection head. As a result, these are not located parallel to a main flow direction in the mixing space. The atomization and mixing in the mixing space are thereby improved.

It is favorable if the porous plate extends in an angular range smaller or equal 180°. This means that fluids can be injected over the entire surface region of the porous plate toward the mixing space, thus optimizing the atomization and mixing.

It is favorable if a cover element is provided, at least one further supply space being arranged between the cover element and the partition. One or more fluids for injection into the mixing space can be provided by means of this at least one further supply space for the injector elements. The supply of fluid or fluids into the at least one supply space can in turn be carried out in a simple manner.

It may be provided that a support element, by means of which the porous plate can be supported on the injector element, is associated with an injector element. Generally, the pressure in the at least one fluid supply space between the partition and the porous plate is greater than in the mixing space, so that a fluid or several fluids are able to be injected by way of the porous plate into the mixing space. The basic possibility exists of the pressure conditions being reversed, for example, because of combustion disturbances. The porous plate can then be supported on the injector element by means of the provided support element to thus keep said plate on the injection head.

In particular, the support element is at least partially arranged in the fluid supply space between the partition wall and the porous plate. As a result, the support element can provide a contact face for the porous plate, which provides a support function.

The support element may in this case, be part of the injector element or arranged thereon, in other words, it may be an integral component of the injector element or it may be retro-fitted thereon and in particular fixed.

In an embodiment which is simple in terms of production, the support element is configured as a sleeve. The sleeve can be easily pushed onto the injector element and fixed thereon. The sleeve in turn provides a, for example annular, contact face to support the porous plate.

In accordance with the present invention, a mixing chamber is provided, which can be implemented with a short construction and in which a rapid and homogeneous mixing of fluids can be achieved.

In accordance with an embodiment of the invention, an injection head is provided.

The mixing chamber according to an embodiment of the invention has the advantages already described in conjunction with the injection head above.

The mixing chamber in accordance with the present invention can be used, for example, for space travel applications, in chemical plants, in heating systems, in process engineering and in power station engineering.

In one embodiment, the mixing chamber is configured as a combustion chamber. Reactant fluids, namely fuel and oxidants, are injected therein by way of the injection head. These reactant fluids burn in the combustion chamber. In the case of a power unit, the combustion chamber is configured as a thrust chamber.

It is quite particularly advantageous if the mixing chamber has a porous inner casing for effusion/transpiration cooling. During the effusion/transpiration cooling, a cooling medium enters a combustion space and forms a cooling medium film. A reactant fluid may be used in this case as the cooling medium. A combustion chamber can thus be produced, which allows a very high energy density with a relatively low production outlay. The supply of cooling medium to the porous inner casing if a reactant is used as the cooling medium can be integrated into the reactant fluid supply to the injection head.

It is favorable if the inner casing adjoins the injection head. The porous plate of the injection head is supported, for example, on the porous inner casing. A combustion chamber with high mechanical strength and high thermal resistance is thus obtained.

It may be provided in this case that the inner casing and the porous plate are connected. They may have mechanical contact in this case, a corresponding pressing force being exerted. It is also possible for the inner casing and the porous plate to be connected to one another integrally.

It is favorable if an outer casing is provided, one or more distribution channels for cooling medium being arranged between the outer casing and the inner casing. This allows a functional separation to be carried out at the combustion chamber. The outer casing is primarily used for providing the mechanical strength of the combustion chamber. The inner casing is used to provide the thermal resistance of the combustion chamber. Cooling medium can be supplied to the porous inner casing by way of the distribution channel(s).

In particular, the distribution channel(s) is/are in active fluid connection with at least one supply channel for fluid into the fluid supply space between the porous plate and partition. As a result the outlay for providing reactant fluid and cooling medium is kept small. As a result, the mixing chamber can be configured with a minimized number of flanges and the like and can therefore in turn be weight-saving.

It is favorable if one or more nozzles are provided to supply cooling medium into the distribution channel(s). As a result, a partial flow for providing cooling medium can be decoupled, in particular, from a reactant fluid flow, this cooling medium in turn being supplied by way of the distribution channel(s) to the porous inner casing to provide effusion/transpiration cooling.

In particular, the at least one nozzle is configured as a metering nozzle. The quantity of cooling medium provided for the porous inner casing can be adjusted thereby.

It is favorable if a nozzle is arranged on a wall portion which separates the fluid supply space between the partition and porous plate and a distribution channel. This means that the nozzle or nozzles can easily be integrated into the mixing chamber; the outlay in terms of production is minimized.

It is quite particularly advantageous if the outer casing is produced from a fiber ceramic material. The weight of the mixing chamber can thus be kept low. Furthermore, forces can be optimally diverted by means of the fiber reinforcement, so a high degree of mechanical strength is obtained.

It is favorable if a fluid seal for the outer casing is provided with respect to the distribution channels. The outer casing may, in particular, be permeable to fluids with high diffusivity (such as hydrogen). Owing to the provision of a fluid seal it is ensured that cooling medium can only leave a distribution channel in the direction of the porous inner casing.

For example, the fluid seal is formed by means of a foil material and in particular by means of a metal foil.

It is favorable if the outer casing and a cover element of the injection head are connected. As a result, the injection head can be supported by means of its cover element on the outer casing. Flange connections may be provided, for example, for connection.

It is also possible for the outer casing and the cover element of the injection head to be integrally connected to one another.

It is provided that a combustion space of the combustion chamber tapers in a cross section in a direction away from the injection head to obtain optimized combustion properties.

In accordance with the present invention, a power unit having a low weight with a high output and efficiency is provided.

In accordance with an embodiment of the invention, in the power unit the combustion chamber has an inner casing and an outer casing and the outer casing of the combustion chamber is integrally connected to the nozzle wall.

The number of structural elements can be kept small by the solution according to the invention. In particular, no separate connection device for connecting the combustion chamber and the nozzle has to be provided. As a result, the production costs can be kept small and the weight of the power unit can be kept small.

Furthermore, owing to the combination of the combustion chamber and the nozzle to form a unit, the possibility arises of producing the outer casing with the nozzle wall from a fiber ceramic material. A high mechanical strength is thereby produced by a corresponding uninterrupted fiber arrangement.

In particular, continuous fibers are present from the outer casing to the nozzle wall, in other words the fibers are not interrupted. This produces a high mechanical rigidity and strength.

It may be provided that the outer casing is reinforced at the transition region to the nozzle wall. This reinforcement is achieved, for example, by a material thickening at the outer casing and optionally the nozzle wall. It is also possible for a separate covering of the power unit to be provided at the transition region by means of fiber bundles.

It is furthermore favorable if the outer casing is rounded at the transition region to the nozzle wall. As a result, peaks are avoided which may reduce the mechanical strength.

It is quite particularly advantageous if the inner casing is porous to provide effusion/transpiration cooling. During the effusion/transpiration cooling, a cooling medium enters through the porous inner casing into a combustion space of the combustion chamber and forms a cooling film there. The thermal loading of the inner casing may be set below an acceptable limit for the material of the inner casing with the effusion/transpiration cooling.

In particular, one or more distribution channels for cooling medium are arranged between the inner casing and the outer casing. Cooling medium can be supplied to the porous inner casing by way of these distribution channels.

It is quite particularly advantageous if the inner casing is supported on the outer casing in order to ensure a mechanical connection.

It may be provided that the inner casing and the outer casing are supported in the transition region to the nozzle wall. The necessary pressing force is achieved, for example, by a flange connection in the region of an injection head.

For example, the inner casing is supported on the outer casing, and in particular additionally supported, by means of an injection head, which is connected to the inner casing. As a result, a first support point for the inner casing can be provided on the outer casing in the region of the transition region and a further support point can be provided in the region of the injection head. The inner casing and outer casing can thus in turn be fixed relative to one another in a simple manner.

The following description of preferred embodiments is used in conjunction with the drawings for the more detailed elucidation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sectional view of an embodiment of a power unit in accordance with the invention with an embodiment of an injection head according to the invention and with an embodiment of a mixing chamber in accordance with the invention in the form of a combustion chamber;

FIG. 2 shows a sectional perspective view of the power unit according to FIG. 1;

FIG. 3 shows a schematic sectional view of the injection head according to FIG. 1;

FIG. 4 shows an enlarged view of the region A according to FIG. 3;

FIG. 5 shows a variant of the injection head according to FIG. 3; and

FIG. 6 shows a further variant of the injection head according to FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a power unit according to the invention, which is shown in FIGS. 1 and 2 and designated 10 there, comprises a mixing chamber 12, which is configured as a combustion chamber 14. The combustion chamber 14 has a mixing space 16, into which reactant fluids can be injected and can be mixed there. In the configuration as a combustion chamber 14, the mixing space 16 is a combustion space 18, in which combustion processes take place. In this case, (at least) one reactant fluid is a fuel and (at least) one reactant fluid is an oxidant.

The mixing chamber 12 has an outer casing 20 and an inner casing 22. The inner casing 22 delimits the mixing space 16. An injection head 24 (spray-in head) is arranged on the inner casing 22 or this injection head 24 is at least partially a part of the inner casing 22. The injection head 24 delimits the mixing space 16 to one side.

The mixing space 16 is, in particular, rotationally symmetrical to an axis 26.

The injection head 24 is configured, as will be described in more detail below, to be dome-shaped or cupola-shaped.

Distribution channels 28 are arranged between the outer casing 20 and the inner casing 22 of the mixing chamber 12. Cooling medium can be supplied to the inner casing 22 by means of the channels.

The distribution channels 28 are in active fluid connection with a supply device 30. To introduce cooling medium into a distribution channel 28, (at least) one nozzle 32 is provided, which is configured, in particular, as a metering nozzle. It may be provided in this case that a suitable nozzle 32 is associated with each distribution channel 28 or that a common nozzle 32 is associated with a plurality of distribution channels 28.

The nozzle 32 is seated on a wall portion 34, which separates the distribution channel(s) 28 from the injection head 24 and, in particular, from a (first) fluid supply space 36 of the injection head 24.

The distribution channels 28 are oriented substantially parallel to an outer side of the inner casing 22 facing the outer casing 20, so cooling medium can be supplied to the inner casing 22 over a large surface region.

The inner casing 22 comprises a support region 38, by means of which it is supported on the outer casing 20.

The outer casing 20 is preferably produced from a fiber ceramic material. A fluid seal 40 is arranged on an inner side of the outer casing 20 for fluid-tight sealing relative to the distribution channels 28. Said fluid seal is configured in foil form and, in particular as a metal foil. The fluid seal 40 in this case extends into the support region 38 as the inner casing 22 is produced from a porous material, as will be described in more detail below.

The outer casing 20 of the mixing chamber 12 has a flange region 42, by means of which the injection head 24 can be fixed on the mixing chamber 12.

It is basically also possible in this case for the injection head to have a cover element, which is integrally connected to the outer casing 20, so no further flange region has to be provided for connection.

In the configuration of the mixing chamber 12 as a combustion chamber 14, the combustion space 18 tapers away from the injection head 24. The spot in the combustion space 18 with the smallest cross section is located at or close to the support region 38.

A nozzle 44 is arranged as an expansion part at the mixing chamber 12. This nozzle 44 has a nozzle wall 46 and a nozzle space 48. It is arranged, in particular, coaxially to the axis 26 and is configured rotationally symmetrically with respect thereto. The nozzle space 48 widens with respect to its cross section away from the mixing chamber 12 to a nozzle opening 50.

The nozzle wall 46 is integrally connected to the outer casing 20 of the mixing space 12. The nozzle wall 46 is also produced from a fiber ceramic material.

Fibers in the fiber ceramic material in this case run continuously from the outer casing 20 to the nozzle wall 46 through a transition region 52 between the outer casing 20 and the nozzle wall 46. A corresponding fiber course is indicated in FIG. 1 by the reference numeral 54.

The outer casing 20/nozzle wall 46 is reinforced at the transition region 52 between the outer casing 20 and the nozzle wall 46 and has a greater thickness.

It may basically be provided that a fiber covering 56 of the power unit 10 is present in particular in the transition region 52, with a covering axis, which coincides with the axis 26.

The outer casing 20 and the nozzle wall 46 are produced from fiber ceramic with tensile strength and a unit is formed. The number of connection points such as flanges can thereby be minimized. This, in turn, reduces the production outlay and the total weight. Relatively large mechanical loads can also be absorbed, so the configuration of the outer casing 20 and the nozzle wall 46 with uninterrupted fibers (cf the fiber course 54) can absorb mechanical loads more effectively.

The transition region 52 is rounded to avoid peaks and the like.

The inner casing 22 is produced from a porous material, which is, in particular, open-porous. For example, the inner casing 22 is produced from a porous ceramic material or an oxide ceramic material or a porous metallic material such as, for example, sintered metallic material. The inner casing 22 is produced, for example, from a C/C ceramic material if “fuel rich” combustion processes dominate in the combustion space 18, or is produced from an oxide ceramic material if “ox rich” combustion processes dominate in the combustion space 18.

Cooling medium can be introduced into the mixing space 16 through the porous structure, the cooling medium in particular being a reactant. During operation of the mixing chamber 12 (in particular as a combustion chamber), effusion/transpiration cooling can then be effected. Effusion cooling is generally taken to mean sweating-type cooling without phase transition and transpiration cooling is taken to mean sweating-type cooling with phase transition.

The injection head 24 has a porous plate 58. This delimits the mixing space 16. The porous plate 58 is connected to the inner casing 22. It can be supported in this case on the inner casing 22 or else be integrally connected. The porous plate 58 is produced from an open-porous material such as, for example, a ceramic material. It may also be produced, for example, from a porous sintered metal.

The porous plate 58 has a first side 60, which faces the mixing space 16. This first side 60 is concave.

The injection head 24 has a longitudinal axis, which coincides with the axis 26 when the injection head 24 is arranged on the mixing chamber 12. A centre point of a sphere of curvature of the first side 60 is located on the axis 26.

The porous plate 58 is spherically curved, for example, on the first side 60. Other curvature forms are also possible.

The porous plate 58 also has a second side 62 opposing the first side 60, which second side is convexly curved, in particular. The first side 60 and the second side 62 are preferably parallel to one another. A centre point of a sphere of curvature for the second side 62 is also located on the axis 26. The porous plate 58 is, in particular, dome-shaped or cupola-shaped.

As mentioned above, it is provided in one embodiment that the porous plate 58 is supported on the inner casing 22 (FIG. 3). The inner casing 22 has a corresponding contact face 64 for this purpose.

The injection head 24 furthermore comprises a partition (wall) 66, which is spaced apart from the porous plate 58. The partition 66 has a first side 68, which is concave and faces the second side 62 of the porous plate 58. The first side 68 is, in particular, parallel to the second side 62 of the porous plate 58. It is furthermore provided, in particular, that a centre point of a sphere of curvature for the first side 68 is located on the axis 26.

The partition 66, which is fluid-tight, furthermore comprises a second side 70, which is convex. The second side 70 is parallel to the first side 68. The partition 66 is dome-shaped or cupola-shaped.

Formed between the partition 66 and the porous plate 58 is the first fluid supply space 36, by way of which one or more reactants can be supplied to the porous plate 58, it being possible to inject the fluid by way of the pores of the porous plate 58 into the mixing chamber 12. The first fluid supply space 36 thus forms a distribution space for reactant fluid is to be injected into the mixing space 16.

It is basically possible for a plurality of separate fluid supply spaces to be arranged between the partition 66 and the porous plate 58 if, for example, different fluids are to be injected into the mixing space 16 by way of the porous plate 58.

Injector elements 72 are fixed to the partition 66. The injector elements 72 run proceeding from the partition 66 through recesses in the partition 66 and through the first fluid supply space 36 and through recesses 74 in the porous plate 58. The injector elements 72 are fluid-tight here with an inlet 76 and an outlet 78 in each case. Fluid can be introduced into the corresponding injector element 72 by way of an inlet 76. The outlet 78 opens into the mixing space 16.

The inlets 76 of the injector elements 72 are connected to a second fluid supply space 80, which is located above the partition 66 and is delimited in a fluid-tight manner by the latter. The second fluid supply space 80 is a distribution space for a reactant fluid, which is to be injected by way of the injector elements 72 into the mixing space 16.

It is basically possible here for the partition 66 to delimit a plurality of second fluid supply spaces 80. This may be expedient, for example, if different fluids are to be injected by way of the injector elements 72 into the mixing space 16.

The second fluid supply space 80 is outwardly delimited by a dome-shaped or cupola-shaped cover element 82. The cover element 82 is, for example, produced from a ceramic material. A fluid seal 84, which is configured, for example, in foil form, is arranged on the cover element 82 toward the second fluid supply space 80. The second fluid supply space 80 is sealed in a fluid-tight manner with respect to the cover element 82 by means of the fluid seal 84.

The cover element 82 has a flange region 86 for cooperation with a flange region 42 of the outer casing 20.

As mentioned above, it is also basically possible for the cover element 82 to be integrally connected to the outer casing 20. No flange regions are then necessary.

The flange regions 42 and 86 cooperate with one another. For this purpose, continuous recesses 88 a, 88 b are provided on the flange region 42 and on the flange region 86 in each case, recesses 88 a and 88 b being oriented in an aligned manner. A screw 90 is in each case guided through the recesses 88 a, 88 b. Said screw has a screw head 92, by means of which a pressing force can be exerted on the flange region 42. It also has a nut 94, by means of which a pressing force can be exerted on the flange region 86. A washer element 96 used for the uniform distribution of the pressing force is arranged between the screw head 92 and the flange region 42. This washer element 96 is configured, for example, as a half-ring.

A washer element 98, which is also used to distribute the pressing force, is also arranged between the nut 94 and the flange region 86. The washer element 98 is also formed, for example, as a half-ring.

A plurality of screws 90 are also provided, in particular, for fixing the injection head 24 on the mixing chamber 12, in this case.

Through the flange region 86 of the injection head 24 (at least) one supply channel 100 leads into the first fluid supply space 36. This fluid supply channel 100 is in active fluid connection with the supply device 30. Reactant, which can be injected by way of the porous plate 58 into the mixing space 16, can be supplied to the porous plate 58 by way of said fluid supply channel.

The wall portion(s) 34, on which these or the nozzles 32 are arranged, delimit the supply channel 100 to the distribution channel(s) 28 between the inner casing 22 and the outer casing 20 of the mixing chamber 12.

During the effusion/transpiration cooling, the reactant, which is injected by way of the porous plate 58 into the mixing space 16, can be supplied to the distribution channel(s) 28 and can be used for effusion/transpiration cooling by way of the porous inner casing 22.

A supply channel 102, which is in active fluid connection with the second fluid supply space 80, also passes through the flange region 86 of the injection head 24. The injector elements 82 can be “supplied” with a fluid to be injected by way of this supply channel 102.

If a plurality of different fluids are to be correspondingly injected by way of the porous plate 58, a plurality of supply channels are correspondingly provided for the supply channel 100. If a plurality of fluids are to be injected by way of injector elements 72, a plurality of supply channels are present corresponding to the supply channel 102.

The injector elements 72, which are fluid-tight between their respective inlet 76 and outlet 78, pass through the first fluid supply space 36. They are fixed to the partition 66. For example, these are welded on or soldered on. The fixing is such that no fluid exchange can take place between the first fluid supply space 36 and the second fluid supply space 80. For example, a seal 104 (FIG. 4) is provided. This seal is formed, for example, by a weld seam.

The injector elements 72 are tubular. In particular, these are straight with a longitudinal axis 106. They have a cylindrical annular casing 108. This annular casing 108 is produced, for example, from a metallic or a ceramic material.

The arrangement of the injector elements 72 is directed to the application. The injector elements 72 are arranged distributed, with them being arranged distributed in an angular region in relation to the longitudinal axis 26 and also arranged distributed about this axis 26 itself. In one embodiment, the injector elements 72 are arranged uniformly distributed.

A large number of injector elements is provided, in particular. For example, the number of injector elements 72 is more than fifty.

It is, in this case, provided, in particular, that all or the majority of injector elements 72 are arranged at an angle with respect to the axis 26.

It may be provided that a support element 110 is associated with an injector element 72. The porous plate 58 can be supported by means of this support element 110. This may be expedient if the internal pressure in the mixing space 16 is greater than the pressure in the first fluid supply space 36.

For example a support element 110 of this type is formed by a sleeve 112 (FIG. 4), which is arranged on a corresponding tube or in which at least a part of the tube is formed. The corresponding injector element 112 is fixed to the partition 66 by means of this sleeve 112 and the sleeve 112 enters into the first fluid supply space 36. It has an annular contact face 114, on which the porous plate 58 can be supported.

The partition 66 may be supported on the inner casing 22 of the mixing chamber 12.

Arranged in a central region of the injection head 24 is (at least) one injector element 116, which is configured as an igniter to bring about an ignition process in the mixing space 16, as a combustion space 18. The injector element 116 is in this case preferably connected by means of a corresponding supply device 118 to a device for providing the ignition energy or for providing an ignited mixture.

The arrangement of the injector elements 72 depends on the application. In this case, a symmetrical arrangement may be provided.

It is possible, for example, for the longitudinal axes 106 of the injector elements 72 to intersect in a plane 120 which comprises the axes 26. In a further embodiment, the longitudinal axes intersect on the axis 26 (FIG. 5).

In a further embodiment, the longitudinal axes 26 intersect at a point 122, which is located on the axis 26 (FIG. 6). This point is, in particular, the centre point of the sphere of curvature for the porous plate 58 and the partition 66. In this case, the injector elements 72 are oriented radially.

The power unit according to the invention functions as follows:

A reactant A is introduced by way of the supply channel 102 into the second supply space 80. From there, the reactant A flows through the injector elements 72 into the combustion space 18.

The reactant B is introduced by way of the supply channel 100 into the first supply space 36. From there, it flows through the porous plate 58 into the combustion space 18. Furthermore, it flows through the nozzle or nozzles 32, which ensure a corresponding metering, into the distribution channel(s) 28. Through the porous inner casing 22, the reactant B can then arrive as a cooling medium in the combustion space 18 and ensure effusion/transpiration cooling.

A combustion of the reactant A and the reactant B takes place in the combustion space 18, it being possible for the reactant A to be the fuel or the oxidant and the reactant B to be the oxidant or the fuel.

The ignition takes place by means of the injector elements 116, which are configured as igniters.

It is possible as a result of the solution according to the invention to obtain a high energy density in the mixing space 16/combustion space 18. As a result, a high degree of power and efficiency can be obtained for the power unit 10 with a high combustion chamber pressure. The outer casing 20 carries the entire mechanical loading produced by the mixing space pressure. However, it is only loaded by the temperature of the reactant, which flows in the distribution channels 28. The cooling film formed by the effusion/transpiration cooling on the inner casing 22 allows the surface temperature in the transition region 52, where the nozzle wall 46 comes into direct contact with hot gas, to be reduced to a material-compatible range.

A highly efficient mixing and atomization of the reactants is obtained, with minimized spatial requirement, by the injection head 24 according to the invention.

A high degree of mechanical strength in relation to the pressure in the first fluid supply space 36 and the second fluid supply space 80 is obtained by the dome-shaped or cupola-shaped configuration of the porous plate 58.

A large contact surface between reactant A and reactant B at the entry into the combustion space 18 is obtained by the large number of “small” injector elements 72 in comparison to the total inner face of the porous plate 58. As a result a rapid and homogeneous mixing of the reactants is obtained and the reaction zone is minimized. A pre-mixture of the reactants A and B then flows during operation into the actual reaction zone into the combustion space 18. A rapid jet decay is obtained by the provision of injector elements 72, which enter through the porous plate 58. As a result, the length of the reaction zone in the combustion space 18 can be reduced, so the combustion chamber 14 can be produced with relatively small spatial dimensions. A weight saving is in turn obtained.

The atomization and mixing can be improved by a non-parallel orientation of the injector elements 72 in relation to the axis 26, the main flow running parallel to the axis 26.

The supply of reactant takes place by way of the entire surface of the injection head, so the use of space is optimized. A high degree of tolerance relative to local deviations in the reactant fluid introduction is also obtained. The tolerance relative to local deviations is relatively low, for example, with a coaxial flow supply.

An adaptation to the special application can be effected by the orientation of the injector elements. Depending on the application, the distribution of the injector elements 72 may be varied and the diameters of the injector elements 72 may also be varied. In this manner, an optimal atomization and mixing of the reactants can be achieved.

The injection head 24 can be produced in a simple manner. For example, the porous plate 58 is produced and provided with bores for the injector elements 72. The injector elements 72 are fixed to the partition 66 and in particular to bores there, for example by means of laser welding. It is possible, for example, for the porous plate 58 with the bores to be produced first, the injector elements 72 are then introduced into the bores and subsequently the partition 66 is attached. The injector elements 72 can be fixed in an automated manner to the partition 66, for example by means of a welding robot.

A production method of this type can be carried out with relatively little outlay. In contrast to conventional injection systems, no highly precise manufacturing with the most minimal tolerances is required.

The injector elements 72 can be produced from conventional metallic or ceramic tubes.

A high mechanical strength can be achieved by the integral connection of the outer casing 20 to the nozzle wall 46 with efficient cooling by means of effusion/transpiration cooling and allows very high combustion chamber pressures in the order of magnitude of 200 to 400 bar with extremely high thermal loading.

Ceramic materials can be used, in particular for the outer casing 20 and the nozzle wall 46 as well as for the cover element 82. Furthermore, ceramic materials can be used for the inner casing 22 and the porous plate 58. As a result the power unit 10 can be configured with a low weight.

The construction according to the invention in this case is such that good adaptation to the properties of ceramic materials is possible.

Furthermore, the number of structural elements can be minimized and minimized production costs are thus produced. Furthermore, the weight can thereby be kept low.

It is also possible, for example, to minimize the supply lines. These may be arranged in one plane, for example. As a result, no additional distributor has to be provided. For example, the supply channel 100 can be used both to supply reactant and cooling medium. As a result, the complexity is reduced and a weight saving and space saving are produced.

The distribution channels 28 are adapted with regard to their geometric configuration in such a way that, taking into account the variable thermal loading of the inner casing 22 and the pressure distribution, a high cooling efficiency is achieved. 

1. Injection head for injecting fluids into a mixing space, comprising: a porous plate with a concave first side, which faces the mixing space, and with a second side; a partition wall with a first side, which faces the second side of the porous plate, and with a convex second side; at least one fluid supply space, which is arranged between the partition wall and the porous plate; and a plurality of injector elements, which run through the partition wall and the porous plate and in each case open with an outlet into the mixing space.
 2. Injection head according to claim 1, wherein the porous plate has an open-porous structure.
 3. Injection head according to claim 1, wherein the porous plate is produced from a ceramic material.
 4. Injection head according to claim 1, wherein the partition is fluid-tight.
 5. Injection head according to claim 1, wherein the first side of the partition wall is concave.
 6. Injection head according to claim 5, wherein the first side of the partition wall is substantially parallel to the first side of the porous plate.
 7. Injection head according to claim 1, wherein the first side and the second side of the partition wall are substantially parallel to one another.
 8. Injection head according to claim 1, wherein the second side of the porous plate is convex.
 9. Injection head according to claim 8, wherein the second side of the porous plate and the second side of the partition wall are substantially parallel to one another.
 10. Injection head according to claim 1, wherein the first side and the second side of the porous plate are substantially parallel to one another.
 11. Injection head according to claim 1, wherein the injector elements have an inlet, which opens into at least one further fluid supply space in each case.
 12. Injection head according to claim 11, wherein the further fluid supply space is delimited by the partition wall and a cover element.
 13. Injection head according to claim 1, wherein the injector elements are in each case configured so as to be fluid-tight between an inlet and the outlet.
 14. Injection head according to claim 1, wherein the injector elements pass through the fluid supply space between the porous plate and the partition wall.
 15. Injection head according to claim 1, wherein the injector elements are tubular.
 16. Injection head according to claim 1, wherein the injector elements are straight.
 17. Injection head according to claim 1, wherein the injector elements have a cylindrical annular casing.
 18. Injection head according to claim 1, wherein the injector elements are produced from a metallic material.
 19. Injection head according to claim 1, wherein the injector elements are fixed to at least one of the partition wall and the porous plate.
 20. Injection head according to claim 1, wherein the injector elements are arranged uniformly distributed.
 21. Injection head according to claim 1, wherein at least one injector element is configured as an igniter.
 22. Injection head according to claim 19, wherein the injector element(s), which are configured as igniters, are arranged centrally.
 23. Injection head according to claim 1, characterized by an axis, on which lies the centre point of a sphere of curvature of the first side of at least one of the porous plate and of the second side of the partition.
 24. Injection head according to claim 23, wherein injector elements are arranged distributed about the axis of the injection head.
 25. Injection head according to claim 23, wherein injector elements are arranged distributed with respect to the angle of their respective longitudinal axis to the axis of the injection head.
 26. Injection head according to claim 23, wherein the longitudinal axes of the injector elements intersect a plane, which contains the axis of the injection head.
 27. Injection head according to claim 23, wherein the longitudinal axes of the injector elements intersect the axis of the injection head.
 28. Injection head according to claim 23, wherein the longitudinal axes of the injector elements intersect at one point.
 29. Injection head according to claim 23, wherein the injector elements are radially oriented.
 30. Injection head according to claim 23, wherein all or the majority of injector elements are arranged inclined with respect to the axis of the injection head.
 31. Injection head according to claim 1, wherein the porous plate extends in an angular range which is less than or equal to 180°.
 32. Injection head according to claim 1, wherein a cover element is provided, an at least one further fluid supply space being arranged between the cover element and the partition wall.
 33. Injection head according to claim 1, wherein a support element, by means of which the porous plate is adapted to be supported on the injector element, is associated with an injector element.
 34. Injection head according to claim 33, wherein the support element is at least partially arranged in the fluid supply space between the partition wall and the porous plate.
 35. Injection head according to claim 33, wherein the support element is part of the injector element or arranged thereon.
 36. Injection head according to claim 33, wherein the support element is configured as a sleeve.
 37. Mixing chamber, comprising an injection head for injecting fluids into a mixing space, said injection head comprising: a porous plate with a concave first side, which faces the mixing space, and with a second side; a partition wall with a first side, which faces the second side of the porous plate, and with a convex second side; at least one fluid supply space, which is arranged between the partition wall and the porous plate; and a plurality of injector elements, which run through the partition wall and the porous plate and in each case open with an outlet into the mixing space.
 38. Mixing chamber according to claim 37, which is configured as a combustion chamber.
 39. Mixing chamber according to claim 37, comprising a porous inner casing for effusion/transpiration cooling.
 40. Mixing chamber according to claim 39, wherein the inner casing adjoins the injection head.
 41. Mixing chamber according to claim 40, wherein the inner casing and the porous plate are connected.
 42. Mixing chamber according to claim 38, comprising an outer casing, one or more distribution channels for cooling medium being arranged between the outer casing and the inner casing.
 43. Mixing chamber according to claim 42, wherein the distribution channel(s) are in active fluid connection with at least one supply channel for fluid in the fluid supply space between the porous plate and partition.
 44. Mixing chamber according to claim 42, wherein one or more nozzles are provided to supply cooling medium into the distribution channel(s).
 45. Mixing chamber according to claim 44, wherein the at least one nozzle is configured as a metering nozzle.
 46. Mixing chamber according to claim 44, wherein a nozzle is arranged on a wall portion, which separates the fluid supply space between the partition and porous plate and a distribution channel.
 47. Mixing chamber according to claim 43, wherein the outer casing is produced from a fiber ceramic material.
 48. Mixing chamber according to claim 42, comprising a fluid seal for the outer casing with respect to the distribution channel(s).
 49. Mixing chamber according to claim 48, wherein the fluid seal is formed by means of a foil material.
 50. Mixing chamber according to claim 43, wherein the outer casing and a cover element of the injection head are connected.
 51. Mixing chamber according to claim 50, wherein the outer casing and the cover element of the injection head are integrally connected.
 52. Mixing chamber according to claim 38, wherein a combustion space of the combustion chamber tapers in a cross section in a direction away from the injection head.
 53. Power unit, comprising a combustion chamber and a nozzle arranged at the combustion chamber, with a nozzle wall, wherein the combustion chamber has an inner casing and an outer casing and the outer casing of the combustion chamber is integrally connected to the nozzle wall.
 54. Power unit according to claim 53, wherein the outer casing is produced from a fiber ceramic material.
 55. Power unit according to claim 53, wherein the nozzle wall is produced from a fiber ceramic material.
 56. Power unit according to claim 53, wherein continuous fibers are present from the outer casing to the nozzle wall.
 57. Power unit according to claim 53, wherein the outer casing is reinforced at the transition region to the nozzle wall.
 58. Power unit according to claim 53, wherein the outer casing is rounded at the transition region to the nozzle wall.
 59. Power unit according to claim 53, wherein the inner casing is porous to provide an effusion/transpiration cooling.
 60. Power unit according to claim 53, wherein one or more distribution channels for cooling medium are arranged between the inner casing and the outer casing.
 61. Power unit according to claim 53, wherein the inner casing is supported on the outer casing.
 62. Power unit according to claim 61, wherein the inner casing is supported on the outer casing in the transition region to the nozzle wall.
 63. Power unit according to claim 61, wherein the inner casing is supported on the outer casing by means of an injection head, which is connected to the inner casing. 